1. Field of the Invention
The present invention relates to a tourniquet apparatus for controlling the flow of blood through a body member. Specifically, the invention relates to a tourniquet apparatus that will not damage the skin to which it is applied and will exert a substantially uniform pressure thereto.
2. Description of the Prior Art
It is desired to produce a medical tourniquet that is inexpensive to manufacture, and is capable of supplying a uniform pressure upon the perimeter of the body member to which it is applied. Such a tourniquet should be reliable, and should not harm the skin of the patient, even if it is applied for an extended period of time.
Prior art tourniquets have been designed in a plurality of configurations. One common design in the prior art includes a semi-rigid element that is sufficiently flexible to bend with the rest of the tourniquet, but is sufficiently rigid to limit and standardize the radial distention of the air containing bladder or plenum. One patent showing the use of such a semi-rigid member is U.S. Pat. No. 4,979,953 issued to Jerry L. Spence on Dec. 25, 1990. The medical tourniquet of this invention includes an inflatable bladder formed from the welded attachment of two polymer impregnated, fabric wall members. A cover surrounds these wall members, and a stiffener plate is held inside the cover, but outside the bladder.
Other patents utilizing a semi-rigid element are U.S. Pat. No. 4,605,010 issued to James A. McEwen on Aug. 12, 1986; U.S. Pat. No. 4,635,635 issued to Cynthia Robinette-Lehman on Jan. 13, 1987; and U.S. Pat. No. 5,201,758 issued to Dennis Glover on Apr. 13, 1993. The McEwen patent discloses the use of a thermoplastic stiffener wrapped around a bladder, after the bladder has been secured to the patient's limb. This stiffener includes a plurality of holes for receiving pins protruding from the bladder. The mating of the pins and the stiffener removably secures the stiffener to the bladder.
The Robinette-Lehman patent discloses a tourniquet an inflatable bladder with a flexible, two piece exterior backing. A stiffener is positioned between the two pieces of the backing, which are sealed to secure the stiffener therebetween. The Glover patent illustrates an inflatable bladder positioned within a cavity formed between a backing plate and a flexible cover.
Common designs of prior art tourniquets include an air plenum formed from two facing surfaces fused together at their perimeters. U.S. Pat. No. 5,179,957 issued to Michael Williams on Jan. 19, 1993, illustrates a blood pressure cuff formed from a polyurethane nylon sheet folded upon itself. The facing edges of the sheet are fused together to form an inflatable bladder. Appropriate hook and loop fasteners are fused to the surface of the bladder, and are utilized for attaching the cuff to the patient's arm.
Other patents utilizing the technique of welding to secure facing walls of a bladder are U.S. Pat. No. 4,637,394 issued to Gabor B. Racz et al. on Jan. 20, 1987, and U.S. Pat. No. 5,193,549 issued to Matthew Bellin, et al. on Mar. 16, 1993. The Racz et al. patent illustrates a tourniquet having an interior chamber formed from an expansible elastomeric material. One method for securing the edges of this wall to each other is by heat welding. The Bellin et al. patent discloses a cuff having an inflatable compartment defined by a film material. This inflatable compartment is enclosed within a second compartment fabricated from the loop portion of hook and loop fabric. This loop portion is electromagnetically welded to the film material of the inflatable compartment, thus eliminating the need for both adhesives and for sewing.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.